SOMEWHAT surprisingly, Ewen McCallum is not a geek. He is an engaging, funny Scotsman with a passion for the weather which means his high-profile job allows him to indulge in his favourite hobby each day.

His single-minded approach to his subject saw him gear his teenage studies solely towards pursuing a career in the Met Office, where he has worked since 1974.

"I would never describe myself as a geek," the 59-year-old said. "I never had weather instruments in my back garden or anything like that – but I have had a passion for the weather for as long as I can remember."

He recalls in his teenage years thrilling to what caused ferocious storms, and examining smoke coming from chimneys to see how the wind was behaving. "In the same way that some people have a calling towards music or art, I was just born to do it," he said simply.

His long career has seen sweeping changes at his spiritual home, with the methods of calculations at the Met Office evolving from a "pencils and rubbers" exercise to a high-tech operation involving massive supercomputers with a peak performance equalling that of more than 100,000 PCs.

During that time, the accuracy of the forecast has come on in leaps and bounds.

"When I started we didn't operationally have access to satellite pictures, while now they're a really important tool for us to investigate what's going on in the atmosphere," he says. "We didn't have radar, and our view of the world was very limited.

"Forecasting was based on extrapolation. That's OK for a small time period, but when you're looking at a day or two ahead you don't get the development.

"Weather forecasts can go wrong – but a four-day forecast today is about as accurate as a one-day forecast was when I first started. Every ten years, we have gained a day. That will only get better, but we have made huge leaps ahead. In the future, it may be slower."

Of course, it is mainly when the forecast does go wrong that the Met Office finds itself at the centre of the news. Last year's "barbecue summer" headlines turned out to be a washout, and it was also claimed that forecasters had warned that last winter would be mild when it was the harshest for 30 years.

Unusually for a scientist, Mr McCallum sees communication as one of his key roles. He even waved away support from a press officer for our interview. But, while he dismisses the "mild winter" forecast as "mythology", he believes it was the communication which ultimately failed in the now notorious barbecue summer case.

"Because you are looking so far ahead when it comes to a seasonal forecast you need to use probabilities," he said. "The fact is that the public and press don't understand that.

"When you say there's a 65 per cent chance of a warm summer, it still means that there's a 35 per cent chance that there won't be. Getting that information across isn't easy.

"It's one of the big challenges we face, and we have to be innovative to improve."

But, I point out, the headline in a press release issued in spring last year read that it was "odds-on for a barbecue summer". When the Met Office's own staff are putting out such quoteworthy statements, can they be surprised when the media latch on?

"It's fair to say that, with the science of seasonal forecasting still relatively immature, and with a lot of work still to be done, perhaps, with hindsight, we pushed the message too strongly," Mr McCallum conceded. "Any organisation that doesn't learn from its mistakes isn't growing. As well as the meteorology, we have to be careful about how we manage the message, and that's an art. It's a skill to get the balance right between a solid scientific statement and a tabloid headline."

The Met Office has now ditched publication of its seasonal forecasts in favour of monthly outlooks, which Mr McCallum insists has pleased the public.

But he stressed that forecasters never issued a statement saying that last winter would be mild. He said a reporter pulled out one line from a single paper on the agency's website.

"Many more factors than that would have been taken into account when putting out a seasonal forecast," he said. "It was just a nonsense. We had a very good record of short-term forecasts last winter, which is what is used for making strategic decisions relating to roads and salt and so on."

Mr McCallum admitted that a barrage of criticism did have an impact on staff morale, but he believes constructive criticism is "no bad thing".

He said: "People have to understand that not every forecast will be absolutely correct. If we got it right every time, we'd be God. As an organisation we musn't be too defensive.

"Some of the criticism can be justified, but the media can act like a pack of wolves, and there can be a campaign to get the Met Office, or the public sector generally. We have to accept that bashing the weathermen is quite good sport."

Mr McCallum's first year in his post as chief forecaster – his dream job back when he was an ambitious student – was 1987.

It was the year of the great storm which famously caught out presenter Michael Fish, catching the whole of the Met Office off guard.

As responsibility for tallying up the automated models with what is actually happening on the ground lies with the chief forecaster, Mr McCallum could have been in deep water – but he dodged the bullet.

"I was on leave the week of the great storm," he said. "Otherwise, I might not have been talking to you from this position right now." Perhaps modesty stops him from pointing out that he might equally have seen the warning signs where others did not, and been the one to ring the alarm bell.

Despite the more recent furore, Mr McCallum insists that public perception of the Met Office and confidence in its services remain high. "The public has been remarkably robust, despite the media campaign," he said. "We're finding that perception hasn't really changed."

He now believes the key to the future lies in improving both long-term forecasting and ultra-localised outlooks.

"Our biggest success is in forecasting between one and five days, but we have really got to improve in the very short range, in terms of detail, in post-code forecasting.

"At the moment forecasting is quite general, and refers to the South West being cloudy or rainy, but we get really powerful variations on places like Dartmoor, Exmoor and the coasts.

"The detail is getting better, but it's still not as accurate as I would like to see it."

Our discussion takes place against a difficult backdrop of cuts to public services, with the Met Office under on-going threat of privatisation.

Mr McCallum refuses to be drawn on the politics involved, which are outside his remit, but predicts that every organisation will have to accept a share of the funding pain.

Yet all this comes at a time when climate change has never been higher on the agenda – another development during Mr McCallum's career.

It is now widely accepted that in around 50 years' time Britain will see the same conditions as Bordeaux today, but Mr McCallum said the Met Office, which incorporates climate change research at the on-site Hadley Centre, now had to focus more on the regional impact.

"The climate changes we're talking about are quite rapid," he said. "In the past they have happened over hundreds of thousands of years. Our climate is good at adapting, but when it's this rapid it's very difficult."

One team to adapt to change was the Met Office itself, when in 2003 it relocated from scattered offices with no room for expansion in Bracknell, Berkshire, to a custom-built greenfield site in Exeter. Mr McCallum moved with his family and said the operation took an "incredible" amount of effort, but had been a huge success.

The open plan nature of the state of the art building means that even high fliers like Mr McCallum don't get their own office, but each element of the organisation is more integrated. "In standard offices you have to knock on someone's door but here you're always bumping into people," he says.

He also believes the move may have instilled confidence in other organisations to follow suit, and to have contributed to Exeter seeking to establish itself as a city of science.

In the years before he retires Mr McCallum's remaining ambition is to nurture young talent as it comes through the Met Office's on-site college.

He said: "I have been really lucky. Every job has its pressures and the odd bad Monday, but for me this has been a vocation. Sometimes it's like being paid to do my hobby. My job satisfaction is very, very high."